Control system



May 23, 1939. w. D. HALL CONTROL sxsmu Filed Dec. 9, 1936 4 Sheets-Sheet l I I I Z //fl /W 1 Q: I/ Q N A V l// 1 /Z mu May 23, 1939. w. D. HALL CONTROL SYSTEM Filed Dec. 9, 1936 4 Sheets-$heet 2 23, 1939- w. D. HALL 2,159,658

CONTROL SYSTEM Filed Dec. 9, 1936 4 Sheets-Sheet 3 May 23, 1939.

W. D. HALL CONTROL SYSTEM Filed Dec. 9, 1936 4 Sheets-Sheet 4 I (D-ml L I O fi/METALL/C v '1 l mlsl/LAT/o/v FIDO I'll II 1 I ll [fire/7 tor-- Patented May 23, 1939 UNITED STATES PATENT OFFICE CONTROL SYSTEM William D. Hall, Elkins, .W. Va.

Application December 9, 1996, Serial No. 115,270

za Claims.

This invention relates to control systems and more particularly to means for automatically igniting the fuel at a gas burner and has for its objects to delay the opening of the fuel valve 6 until the igniter has reached igniting tempera-.

ture; to close the fuel valve whenever the flame is extinguished; to delay reopening of the valve and reignition until any unburnt gas has escaped; to break the ignition circuit after ignii tion has been elected; to remove the igniter from close proximity with the flame; to close the fuel valve if ignition is not effected, and to guard against opening of'the fuel valve when the igniter is burned out.

I have found that prior to the arrival of gas at a hot wire gas igniter certain quantities of air are discharged adjacent the igniter and occasionaliy such air will have sufllcient cooling effects on the igniter that the gas will fail to Q ignite. To overcome this effect, I have provided means for repeatedly operating the igniter and the valve so that if the gas fails to ignite, the valve will be closed for a short period. Ordinarily, upon reopening of the valve, the gas will a ignite immediately. To perform this result, I utilize a switch which is adjacent the burner flame and which repeatedly opens and closes until it is finally opened by heat dissipations from the burner. Under normal conditions, the switch 90 is opened due to heat from the flame before it has had time to open automatically.

The dominating feature of my invention resides in the provision oi separate switches for controlling theigniter coil, and the valve. These 36 switches are arranged to open and close their circuits at different temperatures of the burner in such a manner that as the burner cools due to an accidental extinguishment of the flame, that the valve will be closed at a higher burner tem- 40 perature than the temperature at which the igniter is masked. This feature prevents the igniter from being energized while gas is issuing from the burner, or while the burner chamber is full of unburnt gas. This principle is more specifically defined in the annexed claims and I will therefore not attempt to recite here the numerous modifications and adaptations of this principle.

In the drawings, 50 Figure l is a schematic diagram of one form of my invention.

Figure 2 illustrates a simplifled arrangement. Figure 3 is an elevation view showing a method of mounting the various elements of the device 56 illustrated in Figure 1.

Figure 4 is a sectional view of Figure 3 taken along the axis 4-4.

Figure 5 illustrates an improved form of my invention.

Figures 6, '1, 8, 9, and illustrate various 6 stages of the operation of the device illustrated in Figure 5. 9

Figure 11 illustrates another form of my invention.

Figure 12 is a side view of the combustion-responsive switch of Figure 11.

Figures 1 to 4 inclusive are duplicates of the drawings of my copending application entitled, Ignition system for gas heaters, flied October 1, 1934, Serial Number 746,435, where there is shown a room thermostat 5 which opens and closes the circuit according to the temperature of the room, the thermostat being connected at one side with the input line 50 and the opposite side connected by a conductor 5| with the igniter 6. The igniter 8 is a helical heating coil located above and close to the burner 19 and is wound on a porcelain strip which is carried by the bimetallic arms 28, 29, secured thereto by bolts 31, 32 and by screws 36 to a porcelain base 21. The igniter 6 is a rather large heating coil and attains red heat. It is sufllciently large that it radiates energy to circuit breaker I and thereby modifies the responsiveness of this circuit breaker to heat from the flame. A conductor 92 leads from the igniter to the circuit breaker i, the contacts I of which are normally closed. This circuit breaker may be of any detailed construction, being shown essentially as a bimetallic disc or diaphragm having its edge engaged with the edge of an iron ring or drum 3|, as shown at 39, the ring being secured by bolts 95 to the insulated base 21. From the contacts 9, a conductor 99 leads into a box or case it of porcelain where it terminates in one of the contacts 9, the other of said contacts being carried by a bimetallic strip III which is connected to the input line 54. A low resistance heater II is inserted in the line It and a high resistance heater forms a shunt around the contacts, that is, between conductors 99 and 54. The contacts are separated by expansion of the strip in due to heat given oil by said heater l I, and to attain certainty in the interaction of the heaters, the box I9 is made rather thick and will store heat for several minutes.

Tapped into the conductor 59 is one end of a solenoid it which has for its core the stem ll of the fuel valve 55. It will be readily seen that the valve will be raised when the solenoid is energized thereby opening valve 55 whereby gas may flow through pipe 58 to the burner, and the valve will be closed by gravity when the solenoid is deenergized. The upper end of the solenoid is connected by a conductor 51 with one end 01. a resistance coil I9, which coil is arranged near the circuit breaker 1, and has its opposite end tapped into the conductor 53. The solenoid and the resistance 19 are therefore in parallel.' The heater I9 is of such size that its heating effects alone will cause expansion of the circuit breaker I to break the circuit after several minutes heating.

A bimetallic strip 14 is arranged near the igniter and is tapped into the conductor 5| by a wire 58. Said strip carries a contact 88 which engages the contact I5, this latter contact being adjustable toward or from the contact H by a screw (see Figure 4). When the gas is ignited, the heat of the flame will cause the arms 28 and 29 to bend and carry the igniter away from the flame. The distance from the flame obviously depends upon the temperature attained by the flame and the burner chamber. Therefore, when the burner chamber is relatively cool or when the gas flame is low, the switch ll will not move very far from the flame and will be heated to a fairly high temperature by the small flame. When the flame is high, the strip M will move an appreciable distance and will therefore not be heated to the extremely high temperature which it would have if it had remained immediately adjacent the flame but will be heated to only a fairly high temperature. Therefore, the adjustment of screw 40 does not appreciably depend upon the height of the flame, and the device will operate uniformly under the influence of changing thermal conditions. Since the thermostatic switch I4 is moved from close proximity to the flame, the time required for it to open its circuit in event the flame becomes extinguished is substantially less than the time interval that would have been required if switch H had remained immediately adjacent the flame.

As was heretofore stated, the igniter supplies heat to the circuit breaker 1. This feature of my invention has the advantage of increasing the responsiveness of the circuit breaker I to the flame without at the same time decreasing the operating temperature of the circuit breaker. Before the flame is established, the igniter preheats circuit breaker 1 and upon establishment of combustion, the circuit breaker will terminate the energization of the igniter, thereafter.

operating in response to heat from the burner and resistance wire l9.

When the thermostat 5 changes from the off to the on position, the circuit is closed through the igniter 6, the circuit breaker 1, contacts 8, 9, strip l0 and small resistance l I back to the source. The igniter heats and raises the temperature of the strip l4 so that it engages the contact l5,

thereby establishing a circuit through the solenoid 'l 6 and back to the line through the strip l0. Consequently, the valve is opened and gas flows to the burner and is ignited, (the action of the parts in' event the gas should fail to ignite is considered temperature than the temperature at which breaker 1 closes its circuit, the valve will be closed and unburnt gas given a chance to escape before reignition is attempted. Upon closure of the breaker I the igniter will be reenergized and an attempt at ignition made. If this attempt at reignition, or if an original attempt at ignition fails, and the gas flows without igniting, the igniter will be deenergized after the heat therefrom with the heat from resistance l9 has caused the circuit breaker I to open. Circuit breaker 1 opens and closes its circuit with a snap action} which I have found to be of importance. If this circuit breaker did not have a snap action, the operation thereof would be unstable inasmuch as upon closure it reenergizes the igniter which liberates heat tending to reopen the breaker. By utilizing the "snap" feature, the breaker will open and close repeatedly with appreciable time intervals therebetween thus making several attempts to ignite the gas. In each event, the resistance I9 is also active and this heater aids in producing the series of ignition attempts, and in fact, it is the operation of this heater which prevents the igniter from being energized before the valve is closed (during the series of ignition attempts). After several ignition attempts, the heat liberated by heater I I will have been stored around strip ill in sufllcient quantity to open the contacts 9 and the high resistance element I2 will be thereby placed in series with the line, and with the igniter, the solenoid, and the resistance element I9. Since resistance element I! has a high value of resistance, it will limit the current through thgigniter etc. to such a low value that the igniter and solenoid will not operate, however there will be suflicient heat liberated in casing l3 due to the heat dissipated by resistance I! to maintainthe contacts 9 open. To restore the system to normal condition, it is necessary to turn off the line voltage until strip I 0 has cooled. If the igniter should burn out, it would be impossible to operate any of the parts as all steps are dependent on the initial heating of the igniter.

In Figure 2, the burner is shown supplied with gas through the valve 2| which has a stem 22. A bimetallic bar 23 is fastened at one end to a flxed bracket 25, and the other end thereof operates the stem 22. The igniter 24 is arranged under the strip 22 and directly over the burner and a time switch 26 is inserted in the igniter circuit. The time switch is closed to energize the igniter and the heat of the igniter actuates the bimetallic strip so that after a definite time interval, the expansion of the strip will open the fuel valve permitting gas to pass to the burner and burst into flame. The flame will keep strip 23 heated, thereby retaining the valve in open position as long as the flame continues to exist. After a definite time interval the switch 26 will automatically open thereby deenergizing the igniter which need not operate once a flame is established.

The type of ignition control system described in connection with Figure 1 is intended for small stoves and heaters which are ordinarily located directly in the room which is to be heated. The devices illustrated in Figures 5 and l0 are more especially adapted for use on hot water heaters, gas furnaces, etc., where it is not desired to vary the height of the gas flame and where it is not objectionable to locate a "flasher in the burner flame. For these latter uses a quick acting device is necessary. The device of Figure 1 acts more quickly at every stage of its operation than the ordinary'devices of the prior art. The ignition devices of Figures 6 and 11, however, are very quick in operation and are capable of recycling at maximum burner temperature within twenty seconds. Ordinarily, however, at maximum burner temperature it is not necessary to relight the burner so quickly an'a'l prefer to add weight to the sliding contacts until the recycling operation takes about one minute. In this case, should the burner attain maximum temperature and for any reason, accidental or intentional, the flame become extinguished, the valve control switch will break its circuit in about ten or fifteen seconds. After one minute the igniter will again be in the circuit and the burner will be relighted if the thermostat calls for heat. With the adjustment of approximately one minute at maximum burner temperature, the recycling operation will. occur in about twenty seconds at moderate burner temperatures. The thermal switches which control this quick operation are all arranged to be safe in their operation and in event of a fault or sticky switch, the gas cannot escape without igniting.

Referring to Figure 5, current is supplied tothe control system through .the room thermostat RT and the safety switch S8 and to the metallic supports II and 16 which are preferably composed of stainless steel. These supports are mounted on a base. such as the base 21 of Figure 4. Slidably supported by the supports II and 16 are bars 16 and II which are also composed of some form of stainless steel. The current traversing from support II to bar I6 is negligible and the sliding contact is amplysuflicient whereas for bar 11 it is preferable to insert a small flexible conductor in parallel with the sliding contact l1, It.

The strips or bars 16 and I1 are not rigidly fastened to supports II and 16 but are arranged. to slide through these supports. Hence, the bars will move when the bimetallic strips exert a force on them. Mounted on the base 66-66 are the bimetallic strips 66 and 19 which respectively carry contacts 64 and 66. The leg 66 of movable member 16 is composed of an insulating material and consequently when this member is engaged by the bimetallic strip 66, nocurrent will flow in the circuit 62; however, the short leg or rial. When the burner is cool, the bimetallic strips have a relationship to the sliding members such as is illustrated in Figures 5 and 6. Stops 66 and M illustrated as dotted rectangles are fastened to bars H and I1 and prevent these bars from moving any farther to the right than their illustrated position. Said stops are in engagement with the stationary supports II and 16 when the burner is cool. Disposed adjacent the bimetallic strip 66, I have located the heating element 63 which may radiate heat to strip 66 but due to baflle 66 it cannot radiate heat to the bimetallic strip 16. In operative relation with one jet of the burner, I have located a "flasher 6| which consists of a hollow body portion having a hole near one end thereof; The igniter 62 is located adjacent said hole and is connected in series with switch 66 and resistor 63. In the appended claims, the word igniter" or the words ignition means" are considered broad enough to cover such variations in my principle wherein an added resistor is connected to the igniter-proper of Figure l, the resistor serving to heat the thermal member ll. The flasher 6| may be used with either of my other forms of devices but it is not recommended when the products of combustion of the stove are discharged into the room which is to be heated.

The principle of operation of the device which is illustrated in Figure 5, may be explained in the following manner. RT closes the circuit, only one current path exists and this path may be traced as follows: ll-l6- 1'| '|6-66'|9igniter 62-resistor 63-88- RT. The current flow through the igniter raises the temperature thereof to igniting temperature and the heat radiated from resistor 66 to bimetallic strip 66 causes this strip to flex. The original positions of the bimetallic strips are illustrated in Figure 6. When heated, strip 66 flexes until contacts 64 and 66 engage each other. This relationship of parts is illustrated in Figure 7 and allows current to flow through two paths, one similar to the circuit previously recited, the other comprising: ll-'|4-66--646662'I2S8- RT. The energization of solenoid I! causes the valve to be opened thereby establishing a flow of gas to the ,burner. In event that the flow of gas should fail to ignite, the arrangement of parts illustrated in Figure 7 will not change'appreciably until after a definite period of time when the safety switch will trip to its open position thereby deenergizing the igniter and the solenoid 12. In construction, the safety switch 88 may be similar to the switching arrangement in casing II of Figure 1. Under normal conditions, the safety switch never operates due to the fact that gas from the burner flows into flasher 6i and is ignited by igniter 62. Upon ignition, the gases in the hollow body portion of said fiasher expand and tend to pass out of the flasher; however, since the hole adjacent the igniter is relatively small practically no flames will pass out of this hole. Consequently, the greater percentage of the ignited gases in flasher'6l flash over the burner ports 81 and 66 igniting the gases which emanate When the room thermostat from those ports. The entire supply of fuel is I soon ignited and the heat therefrom causes the bimetallic strips to bend to the left thereby opening contacts 66. In Figure 8,v I have illustrated the relationship of the parts just after the igniter circuit is broken. As the burner continues to heat, the bimetallic strips 66 and I. continue to move the members 14 and 11 to the left until at a very high temperature they reach a position such as is illustrated in Figure 9. At this position, assume that the gas supply is accidentally stopped and immediately restarted, or assume that the room thermostat RT is turned off and immediately turned back on. In either of these cases, the fire would be extinguished and when the flow of gas resumes it would escape. However, I have provided a control switch capable of recycling, and therefore, within a short period of time the burner will cool a few degrees and the bimetallic strips 66 and 16 will disengage members 69 and 16 respectively. This operation is performed quickly due to the sliding feature hereinbefore mentioned. Immediately upon such disengagement the circuit to the valve is broken, but the igniter will not be reenergized until a later period of time due to the fact that in addi tion to disengagi fl the member I6, the contact 66 must traverse the distance D (of Figure 9), before it closes its circuit, (see Figure 10). When the igniter switch recloses, resistor 63 will raise the temperature of strip 66 until contact at 84 is remade. This latter action will reopen the valve 13 and an attempt to relight the burner will be made as heretofore stated.

It is specifically pointed out that the sliding feature is a substantial improvement over a control system in which members H and 11. do not move. However, this improvement should not act as a limitation to my broader claims as such are clearly of sufficient scope to cover the simple, yet effective, system wherein contact members 14 and TI are stationary. In fact, my principle is even broader than electrical circuit arrangements specifically recited above, and rather than attempt to list the numerous modifications which I have experimented upon and conceived, I am defining the principle in the appended claims.

The control system of Figure 11 illustrates an improved form of sliding contact, in which the contacts rotate. Member Si is pivoted to support by means of the pivot 92. Bimetallic strip 91 is solely and rigidly supported at its left end and moves the rotatable structure with its free end. The metallic member 9i carries the insulating member 94 and the metallic contact 93. When the burner temperature is failing, the strip 9! engages insulating member 94, whereas as the burner temperature is increasing, the contacts 93 and 96 are in engagement. Operatively related with strip 91 and in series with igniter 99, I have connected the heating element 98. The thermal switch 91 is associated with the burner flame, however, I prefer not to associate thennal switch iill with the heat from the burner. This latter thermal switch is heated by passage of current therethrough from the current transformer Hill. The contacts of thermal witch iili are closed when the switch is cool current from the current transformer) and open when the switch is hot. The primary winding (high voltage or low current) is connected in series with member 9i and the gas valve solenoid I02.

When the thermostat calls for heat, current passes through the igniter circuit, through thermal switch HH and to the supply line. Upon closure of contacts 93-96 due to heat from element 98, the valve is opened and thermal switch iOi is energized. If the flame ignites, contacts 93 and 96 will remain in engagement, but if for any reason, the gas fails to ignite the heat generated in switch iili will break the igniter circuit, and the current transformer will remain energized until resistor 98 has cooled and strip 91 disengaged its contacts. When such disengagement occurs, switch i0l will close after a delay due to its thermal capacity, an inherent feature, and will make another ignition attempt. If several such attempts are unsuccessful, the safety switch will operate. Should the burner properly ignite and operate for any period of time after which the supply of gas should temporarily cease, strip 91 will cool and quickly open the valve circuit. As soon as switch Iili recloses, an attempt to relight the burner will be made by reenergizing the igniter and element 98, the latter reheating switch 9'! to thereby close its contacts.

In each ignition control, the valve arrangement of Figure 2 may be substituted for the solenoid valve with a consequent saving in cost.

This application is a continuation in part of my prior copending application #746,435, filed in the United States Patent Office on Oct. 1, 1934, and entitled Ignition system for gas heaters.

I claim to have invented,-

1. In combination, a burner having means controlling the feed of fuel thereto and an ignition system comprising, an igniter, an electric heater, means controlled by heat from said igniter for energizing said heater, and thermostatic means operatively associated with said heater and burner for controlling energization of said igniter.

2. In combination, a burner, a circuit including means for permitting the flow of fuel to said burner when the circuit is closed and preventing said fiow when the circuit is open, and a control system comprising ignition means, a thermal switch responsive to combustion which opens when heated and closes when cooled in series with and controlling energization of said ignition means, and a thermal switch responsive to both the heat of combustion and the heat from said ignition means which closes when heated and opens when cooled in series with and controlling the energization of said circuit; said thermal switches being so constructed and arranged that as the burner cools the second thermal switch will open before said first thermal switch recloses.

3. In a burner control system, in combination, a burner, ignition means having an electric circuit for energizing the same, thermostatic means for breaking said circuit responsive to heat, an electric heater operatively associated with said thermostatic means, and a circuit including means for permitting a. flow of fuel to said burner and for preventing said flow and having a heat responsive circuit closer therein which closes in response to heat from said ignition means; said electric heater being connected to said fuel control circuit whereby heat from the ignition means will establish a flow of fuel and heat from said heater will break the ignition circuit.

4. In a heating system, a space wherein fuel is burned, starting means including an electrically operated igniter for igniting the feed of fuel passing into said space, a thermal switch responsive to heat from said space for controlling the energization of said igniter, and fuel control means for said space including a thermal member with means adjacent the member relative to which the member moves in response to heating and cooling of the member, said starting means being operable to effect relative motion of said member and its adjacent means, said fuel control means having means cooperating therewith for initiating feed of fuel to said space in response to such relative motion of said member and its adjacent means as is produced by said starting means and for reducing the feed of fuel to said space when said member operates in response to changing thermal conditions which may indicate faulty delivery of heat by said system, said thermal devices being so constructed and arranged such that in response to said changing thermal conditions the said thermal member will operate prior to the closure of said igniter circuit by said thermal switch.

5. In a heating system, a first-means where fuel is burned, an electrically operated igniter for igniting the feed of fuel passing to said firstmeans, a thermal switch responsive to heat from said first-means for controlling the energization of said igniter, and fuel control means for said first-means, said fuel control means including a thermal member and means cooperating therewith for reducing the feed of fuel to said firstmeans when said member operates in response to changing thermal conditions of the system which may indicate faulty operation of a portion of the system, said thermal devices being so constructed and arranged such that in response to said changing thermal conditions the said thermal member will operate prior to the closure of the igniter circuit by said thermal switch and thereafter said thermal devices willalternately operate thereby recycling the system.

6. In a heating system, in combination, a space wherein gas may be burned, an electrical igniter for initiating combustion of the gas to be burned, a circuit breaker controlling the operation of said imiter, a thermal element close to said circuit breaker for operating the same to open the circuit breaker when combustion is established and to reclose the circuit breaker if combustion accidentally extinguishes for a period of time, a wall separating said space and said circuit breaker thereby insulating said circuit breaker from direct contact with the products of combustion, whereby the said wall inherently also increases the time lag of response of said circuit breaker to temperature changes of said space, means. for reducing said increased time lag of response by modifying the quantity of energy which said thermal element would ordinarily otherwise receive, and fuel control means comprising a temperature responsive actuator which operates in response to predetermined changing thermal conditions of the heating system to reduce the feed of fuel to said space in response to a fault of the system, said actuator and said circuit breaker being so constructed and arranged that in response to continuance of the fault which caused initial operation of said actuator the said actuator and said circuit breaker will operate in such a manner as to attempt to relight the fuel with said actuator initially operating flrst.

'7. In a heating system. in combination, a heater where gas may be burned, an igniter for initiating combustion of the gas to beburned, a heat responsive circuit controlling device which deenergizes the igniter in response to heat from said heater and energizes the igniter when the temperature "of said heater falls below a predetermined point, and a device for reducing the time lag of response of said circuit breaker comprising means which when energized reduces the heat transfer rate from said heater to said circuit breaker, and a switch which receives heat from said heater and is arranged to open and deenergize said means when the temperature of said heater falls below a predetermined point.

8. A device which is adapted to be placed adiacent a burner to control the operation thereof comprising a circuit including means for heating a portion of the fuel to the ignition temperature, a switch responsive to combustion to open said circuit upon establishment of combustion and to reclose said circuit when combustion ceases, a circuit including means for permitting a flow of fuel -to said burner and for preventing said flow, a switch controlling'said fuel control circuit which responds to a passage of current through said ignition circuit to start a flow of fuel and also responds to combustion to retain a flow of fuel during periods of satisfactory combustion and which stops the flow of fuel when combustion ceases, said switches being so constructed and arranged such that as the burner cools due to extinguishment of the flame said second-mentioned switch will operate to stop said flow of fuel before said ignition circuit is reclosed by said first-mentioned switch.

9. In combination, a burner, and a control system comprising thermal means operatively related with the'burner for controlling-the feed offuel thereto to permit a flow of fuel while said thermal means is expanding and to prevent said flow when said thermal means changes from an expanding motion to a contracting motion, an igniter having an electric circuit for energizing the same, said circuit having means coopcrating therewith for heating said thermal means, and an expansibie and contractable thermal means operatively related with the burner flame for controlling the energimtion of said igniter circuit to open said circuit when said last-means begins to expand and to reclose said igniter circuit after said last-means has contracted a short distance.

Y 10. In combination, aburner and a control system therefor comprising a circuit including an igniter for the burner, means responsive to combustion and to a current flow through said circuit to establish a flow of fuel to said burner and to prevent said flow of fuel, and means responsive to combustion for breaking said igniter circuit when combustion is established-and to reclose said igniter circuit when combustion ceases, said first and second mentioned means being so constructed and arranged such that as the burner cools due to extinguishment of the flame the flrst mentioned means will stop the flow of fuel to said burner before the ignition circuit is reclosed by said second mentioned means. I

ll. In a burner control system, a burner, an igniter for the burner, a circuit including said igniter means for breaking said circuit,responsive to heat, means responsive to an energization of said circuit and to combustion to heat said circuit breaking means, and means operated by said second mentioned means for controlling the feed of fuel to said burner.

12. In an ignition system, an igniter, a circuit breaker in the igniter circuit, said circuit breaker including a heat responsive element which snaps open when heated and snaps closed when cooled below a predetermined temperature and is responsive to heat from the igniter circuit and the flame to such a degree that if the flame fails to ignite the heat from the igniter circuit will repeatedly open and close said circuit breaker with appreciable time intervals between subsequent openings and closures.

13. In combination, a burner, and an ignition system comprising an igniter having an electrical circuit for energizing the same, a fuel circuit including means for permitting a flow of fuel to said burner and for preventing said flow, a thermal switch in said fuel circuit which is responsive to heat from the ignition circuit and the burner, and a second thermal switch which is responsive to heat from the burner flame to break the igniter circuit.

14. A control system comprising a burner, an igniter therefor, a circuit for said igniter a heat responsive circuit breaker in the igniter circuit which opens when heated and closes when cooled, said circuit breaker being positioned adjacent the burner flame, and means for opening and reclosing said circuit breaker if combustion fails to be established on the first effort.

15. In combination, a burner, a thermal member adjacent said burner and responsive to heat therefrom, means operated by said thermal member for controlling the feed of fuel to said burner to initiate said flow when the temperature of the said thermal member increases from its normal room temperature and to prevent said flow when said thermal member has cooled below a predetermined temperature, an electric heater positioned in heat transfer relationship with said thermal member, -a portion of said heater being in igniting relationship with said burner and adapted upon energization to ignite the fuel, and a secondthermal member which operates independently from said first thermal member and controls the energization of said electric heater to close the circuit thereto when the burner cools and open the circuit after the burner has become heated, said second thermal member being positioned adjacent said burner but not immediately adjacent said electric heater, whereby the second thermal member is not operated primarily by said heater, said thermal members being so constructed and arranged such that as the burner cools the said first thermal member will operate to discontinue the feed of fuel before said second thermal member recloses the ignition circuit.

16. A device responsive to the heat generated by a heat generator comprising, thermostatic means, means actuated thereby, and means responsive to the temperature attained by said heat generator for varying the heat transfer relation between said heat generator and said thermostatic means.

17. A device responsive to the heat generated by a heat generator comprising, thermostatic means, means actuated thereby, and supporting means for said thermostatic means, said supporting means constituting a bimetallic strip responsive to heat from the heat generator and carrying said thermostatic means toward or away from the heat generator.

18. In a heating system, in combination, a burner, an electric igniter for initiating combustion of the fuel from said burner, means including a thermal actuator operable to maintain said igniter deenergized or energized in response to the presence or absence of combustion respectively, a thermally movable support on which said actuator is mounted, said support being positioned adjacent said burner and operable to move said actuator toward or away from said burner according as the temperature thereof is decreasing or increasing, to thereby maintain said actuator at a predetermined maximum temperature during combustion and enable a reduced time lag of response of said actuator when combustion ceases.

19. In a heating system, in combination, a burner, a circuit controlling the feed of fuel thereto, a thermal switch in said circuit for closing the circuit when heated and opening the circuit when cooled, and a thermally movable support on which said switch is mounted, said support being positioned adjacent said burner and operable to move said switch toward or away from said burner according as the temperature thereof is decreasing or increasing, to thereby enable a reduced time lag of response of said thermal switch when combustion ceases.

20. A device as defined by claim 8 including additionally, an energy integrating device connected to said first-mentioned circuit, and means responsive to the energy integrated by said device for deenergizing said second-mentioned circuit in event the energy integrated by said device exceeds a predetermined relationship.

21. The method of utilizing an igniter of the hot-member type to establish combustion of fuel at a burner which includes heating the igniter, subsequently establishing a flow of fuel at the igniter, stopping the supply of fuel in event it fails to ignite, and immediately reestablishing a flow of fuel.

22. In combination, a burner, an electrical heating device including a fuel igniting portion associated with said burner, and thermal means responsive to the heat of combustion at said burner for controlling the flow of fuel thereto and the energization of said heating device, at least a portion of said thermal means being associated with at least a portion of said heating device and so arranged that heat from said heating device affects said thermal means to establish said flow of fuel, said thermal means being so constructed and arranged that when combustion is established the heat thereof will affect said thermal means to deenergize said heating device and when the burner flame accidentally extinguishes due to a temporary cessation of the fuel supply the said thermal means will stop'the flow of fuel and after an appreciable interval of time to permit unburnt gas to escape reenergize said heating device and reestablish a flow of fuel, whereby to relight the burner.

23. The device set forth by claim 2 characterized by a support for said ignition means and said second thermal switch, said ignition means consisting of a coil of resistance Wire wound on said support, and means for controlling the relative position of said support and the burner to maintain said support in close proximity to said burner in absence of combustion and in a position near but a short distance away from the burner in response to combustion of fuel at said burner, wheFeby to enable said igniter and thermal member to be close to and in good heat transfer relationships with the burner prior to combustion as well as to enable a lower operating temperature of the igniter and thermal member during combustion than would be the case if the support remained closely related to said burner.

24. In a heating system, a main fuel burning heater, thermal means responsive to heat from said main fuel burning heater and operable to affect the flow of fuel thereto, and additional means including a thermal member affected by the heat of combustion of said main fuel burning heater, said additional means being operable in response to heating of said thermal member by said main fuel burning heater to reduce the heat transfer relationship from said main fuel burning heater to said first-named thermal means, whereby during normal operation of the system the first-named thermal means does not reach as high a temperature as it would reach in absence of said last-recited means.

25. In a heating system, a main fuel burning heater, electrically operated means having a thermal switching mechanism which is responsive to heat from said main fuel burning heater for controlling the operation of said electrically operated .means, said electrically operated means including an electrical igniter for said main fuel burning heater, and thermal means which receives heat from said main fuel burning heater and affects the flow of fuel thereto, said electrically operated means including means for affecting the temperature of said last-named thermal means to a greater extent than it affects the temperature of the thermal switching mechanism.

26. In a heating system; the combination with a main fuel burning heater of control means cooperating with said heater operable to establish combustion of fuel thereat and including an arrangement whereby first and second efforts to establish combustion of fuel at said heater may be made with the second effort following the first with a short time interval of separation; said control means comprising means affecting the flow of fuel to said fuel burning heater in such a manner that when more than one effort is made to establish combustion of fuel at said heater that fuel flows to said heater during said efforts and is stopped and restarted between efforts; an electrical resistance igniter operatively related with said main fuel burning heater; and means, including contacts directly in series with said igniter, actuated by said fuel-affecting means as well as by combustion conditions to open said contacts upon establishment of combustion and when more than one effort is made to establish combustion at said fuel burning heater to open and close said contacts between efforts, said last-named means including a thermal member located responsive to combustion as well as near to said contacts and arranged such that said member operates to separate said contacts in response to heat of combustion of said fuel at said fuel burning heater.

27. In a heating system, a main fuel burning heater, a fuel feed line to said heater, means adjacent to and cooperating with said fuel feed line to affect the feed of fuel therethrough, wires adapted for connection to a source of electrical supply, and a control system including the following parts all located solely and completely within proximity of said fuel burning heater and affected by heat therefrom, an electrically operated resistance igniter wound for operation at the potential of said wires, a thermal switch directly in series with said igniter and said wires for deenergizing sa d igniter in response to combustion, and a thermal member for controlling said first-named means.

28. The device defined by claim 13 including additionally an electrical heating resistor controlled by said first-named thermal switch and energ'zed concurrently with flow of fuel to said burner, said heating resistor being in heat transfer relation with said second thermal switch.

WILLIAM D. HALL. 

